1. Field of the Invention
This invention relates generally to the field of semiconductor device manufacturing and, more particularly, to a method of dynamically designing a preventative maintenance schedule based upon sensor data, and a system for accomplishing same.
2. Description of the Related Art
There is a constant drive within the semiconductor industry to increase the quality, reliability and throughput of integrated circuit devices, e.g., microprocessors, memory devices, and the like. This drive is fueled by consumer demands for higher quality computers and electronic devices that operate more reliably. These demands have resulted in a continual improvement in the manufacture of semiconductor devices, e.g., transistors, as well as in the manufacture of integrated circuit devices incorporating such transistors. Additionally, reducing the defects in the manufacture of the components of a typical transistor also lowers the overall cost per transistor as well as the cost of integrated circuit devices incorporating such transistors.
Semiconductor devices are manufactured from wafers comprised of a semiconducting material. Layers of materials are added, removed, and/or treated during fabrication to create the electrical circuits that make up the device. The fabrication essentially comprises four basic operations. Although there are only four basic operations, they can be combined in hundreds of different ways, depending upon the particular fabrication process.
Four operations typically used in the manufacture of semiconductor devices are:                layering, or adding thin layers of various materials to a wafer from which a semiconductor device is produced;        patterning, or removing selected portions of added layers;        doping, or placing specific amounts of dopants in the wafer surface through openings in the added layers; and        heat treatment, or heating and cooling the materials to produce desired effects in the processed wafer.        
The technologies underlying semiconductor processing tools have attracted increased attention over the last several years, resulting in substantial refinements. However, despite the advances made in this area, many of the processing tools that are currently commercially available suffer certain deficiencies. In particular, such tools often lack advanced process data monitoring capabilities, such as the ability to provide historical parametric data in a user-friendly format, as well as event logging, real-time graphical display of both current processing parameters and the processing parameters of the entire run, and remote, i.e., local site and worldwide, monitoring. These deficiencies can engender nonoptimal control of critical processing parameters, such as throughput, accuracy, stability and repeatability, processing temperatures, mechanical tool parameters, and the like. This variability manifests itself as within-run disparities, run-to-run disparities and tool-to-tool disparities that can propagate into deviations in product quality and performance, whereas an ideal monitoring and diagnostics system for such tools would provide a means of monitoring this variability, as well as providing means for optimizing control of critical parameters.
Most modern integrated circuit device manufacturing facilities make great efforts in attempting to control the various process operations performed in manufacturing integrated circuit devices. Such efforts typically involve the collection of large amounts of data from a variety of sensors employed in the fabrication facility. These sensors may be integrated within the various processing tools, or they may be part of various offline metrology tools. The data for such sensors may be collected on a routine or random basis. At least some of the data obtained by the sensors is typically stored, at least for some period of time, in one or more databases. Some of the data collected may not be stored for any significant duration. For example, collected data that indicates that the monitored process is performing within an acceptable operating range may be discarded after a period of time.
A variety of different types of process tools are employed in the manufacture of integrated circuits. Examples of such tools are deposition tools, etching tools, ion implant tools, chemical mechanical polishing tools, furnaces, rapid thermal anneal chambers, etc. These types of tools perform, in some cases, very complex and important process operations. Moreover, the tools themselves are very complex pieces of equipment that must be properly maintained so that they can continue to produce the desired results during operation. Accordingly, a preventative maintenance program is normally established for the tools. The preventative maintenance program often involves checking a great number of operating aspects of the process tool. Preventative maintenance programs are typically standardized in the sense that all tools of the same type, e.g., a particular manufacturer's deposition tool, will be subjected to the same type of preventative maintenance procedures. In many cases, the tool manufacturer specifies the precise preventative maintenance procedures to be performed on the tool. Such preventative maintenance, while desirable in one respect, can be very time-consuming to complete. While such tools are down for preventative maintenance care, the overall efficiency of the fabrication facility may suffer. What is desirable is a method and system for performing an appropriate degree of preventative maintenance on the process tools without having excessive down-time for the tools during the preventative maintenance program.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.